Effects Of Micro-irrigation Methods And Irrigation Amount On Growth And Water-nitrogen Utilization Of Spring Wheat In Hexi Region

In order to explore the water-saving and high-efficiency irrigation method and the optimal irrigation amount of spring wheat in Hexi region,this study adopted field experiment using "Yongliang No.4" spring wheat as the experiment material.There were two kinds of micro-irrigation methods,micro-spray irrigation(M1)and drip irrigation(M2),four irrigation levels of 150mm(W1),200mm(W2),250mm(W3)and 300mm(W4)irrigation at medium-late stage(booting to maturity).The effects of micro-irrigation methods and irrigation amount on the growth,yield,water use and nitrogen accumulation of spring wheat under micro-spray irrigation and drip irrigation were studied.The main research results of the experiment are as follows:(1)When useing micro-spray belt for irrigation,the negative effect of insufficient irrigation at medium-late stage of wheat on the plant height was significant,Compared with micro-spray irrigation,drip irrigation was more conducive to wheat tillering in the early growth period,and the negative effect of low irrigation on plant height was less than that of micro-spray irrigation.The yield of each treatment increased first and then decreased with the increase of irrigation amount at medium-late stage.The yield increasing effect of drip irrigation was more obvious than that of micro-spray irrigation,and the negative effect of low irrigation was less than that of micro-spray irrigation.Irrigation of 250 mm at mediumlate stage was the most beneficial to the formation of spike number,and drip irrigation was more conducive to the accumulation of dry matter than micro-spray irrigation.Micro-spray irrigation water 250 mm and drip irrigation water 200 mm obtained the maximum dry matter quality and yield,respectively,the yield was 8106kg/hm2 and 8233kg/hm2.250 mm micro-spray irrigation and 200 mm drip irrigation at medium-late stage were beneficial to the growth and development of Hexi spring wheat at booting maturity stage and the improvement of yield.(2)The water consumption of the wheat field during the whole growth period increased with the increase of the irrigation water amount at medium-late stage.In the early growth period of wheat,the water consumption intensity of micro-spray irrigation was higher than that of drip irrigation,low irrigation treatment will cause water deficit and inhibit the evaporation of farmland water,irrigation of more than 300 mm at medium-late stage was not conducive to the continuous use of water by wheat,Both of them had a significantnegative effect on yield.The micro-spray irrigation water of 250 mm and drip irrigation water of 200 mm at medium-late stage respectively obtained the maximum water use efficiency,respectively 1.83kg/m3 and 2.05kg/m3,which helped to provide good water conditions for wheat growth in the middle and late stages,reduce inefficient water consumption,and improve the water use efficiency of crops,thereby achieving water-saving and high yield.(3)Under the two micro-irrigation methods,with the increase of irrigation amount at medium-late stage,the accumulation of nitrogen in the wheat at the mature stage increased first and then decreased,and each treatment absorbed the largest amount of nitrogen during booting-flowering stage,increased irrigation amount was beneficial for plants to absorb nitrogen.Micro-spray irrigation had a significant negative effect on the nitrogen absorption of wheat at low irrigation,and excessive drip irrigation was unfavorable for wheat ear development and plant uptake and utilization of nitrogen.Nitrogen accumulation of wheat organs in different treatments showed as: grain> stalk and leaf sheath> cob and ying shell>leaves.With the increase of irrigation amount,the increase of irrigation amount at mediumlate stage can increase the nitrogen transfer rate of post-anthesis vegetative organs to wheat grains and the contribution rate of nitrogen to wheat grains.Irrigation with 250 mm at medium-late stage had the best effect.(4)Under different micro-irrigation methods,the cumulative total amount of nitrate nitrogen in the 0~100 cm soil layer showed that micro-spray irrigation was more than drip irrigation,and the effect of drip irrigation on the leaching of nitrate nitrogen in the soil was stronger than that of micro-spray irrigation.With the increase of irrigation amount,the nitrate nitrogen in the shallow soil was gradually moved to the deeper soil.During the mature period,the content of nitrate nitrogen in the 60~100cm soil layer increased significantly.The micro-spray irrigation water is 250 mm or drip irrigation 200 mm can provide good water and fertilizer conditions to the crop root system.